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991.
Xin-You Meng Hai-Feng Huo Hong Xiang 《Journal of Applied Mathematics and Computing》2011,35(1-2):635-661
A kind of three-species system with Holling II functional response and two delays is introduced. Its local stability and the existence of Hopf bifurcation are demonstrated by analyzing the associated characteristic equation. By using the normal form method and center manifold theorem, explicit formulas to determine the direction of the Hopf bifurcation and the stability of bifurcating periodic solution are also obtained. In addition, the global existence results of periodic solutions bifurcating from Hopf bifurcations are established by using a global Hopf bifurcation result. Numerical simulation results are also given to support our theoretical predictions. 相似文献
992.
We present an H1‐Galerkin mixed finite element method for a nonlinear parabolic equation, which models a compressible fluid flow process in subsurface porous media. The method possesses the advantages of mixed finite element methods while avoiding directly inverting the permeability tensor, which is important especially in a low permeability zone. We conducted theoretical analysis to study the existence and uniqueness of the numerical solutions of the scheme and prove an optimal‐order error estimate for the method. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2010 相似文献
993.
This study is intended to develop an intelligent supplier decision support system which is able to consider both the quantitative and qualitative factors. It is composed of (1) the collection of quantitative data such as profit and productivity, (2) a particle swarm optimization (PSO)-based fuzzy neural network (FNN) to derive the rules for qualitative data, and (3) a decision integration model for integrating both the quantitative data and fuzzy knowledge decision to achieve the optimal decision. The results show that the decision support system developed in this study make more precise and favorable judgments in selecting suppliers after taking into account both qualitative and quantitative factors. 相似文献
994.
This paper is concerned with a class of the generalized non-autonomous Nicholson’s blowflies model with time-varying coefficients and delays which is defined on the nonnegative function space. Under proper conditions, we employ a novel proof to establish some criteria to ensure that all solutions of this model converge to an equilibrium. Moreover, we give an example to illustrate our main result. 相似文献
995.
996.
997.
H1-Galerkin mixed methods are proposed for viscoelasticity wave equation.Depending on the physical quantities of interest,two methods are discussed.The optimal error estimates and the proof of the existence and uniqueness of semidiscrete solutions are derived for problems in one space dimension.And the methods don't require the LBB condition. 相似文献
998.
In this paper we study the maximal operators and the convolution operators Tδ associated with multipliers of the form
999.
喷雾颗粒的浓度、粒径等多参数的同时测量是研究喷雾的关键. 对应用全场彩虹技术测量双组分液滴的浓度及粒径分布进行了研究. 基于改进的Nussenzweig理论,对液滴折射率和粒径分布采用无分布函数算法进行最优化求解, 然后通过折射率与浓度的关系反推液滴浓度.用模拟全场彩虹信号对该算法进行了验证, 该算法可准确反演具有单峰分布、双峰分布粒径特征的液滴群的折射率与粒径分布. 并对体积分数从0%到100%的乙醇溶液喷雾进行了实验测量, 结果表明,所测得折射率与理论值符合,粒径分布稳定.该技术在喷雾浓度测量方面具有广阔的应用前景.
关键词:
全场彩虹技术
折射率
粒径
组分 相似文献
1000.
A system is considered, which is subject to external and possibly fatal shocks, with dependence between the fatality of a shock and the system age. Apart from these shocks, the system suffers from competing soft and sudden failures, where soft failures refer to the reaching of a given threshold for the degradation level, and sudden failures to accidental failures, characterized by a failure rate. A non-fatal shock increases both degradation level and failure rate of a random amount, with possible dependence between the two increments. The system reliability is calculated by four different methods. Conditions under which the system lifetime is New Better than Used are proposed. The influence of various parameters of the shocks environment on the system lifetime is studied. 相似文献